Is tuna bony? Tuna is the king of sea fish. Marinated raw tuna

Common tuna or blue (also bluefin, blue, bluefin, red) tuna (lat. Thunnus thynnus) is a species of ray-finned fish of the mackerel family.

Signs. Tuna, like other representatives of this family, has a powerfully developed cutaneous vascular system associated with the choroid plexus of the lateral muscles and the plexus on inner surface liver or in the hemal channel.

Thanks to this development circulatory system The body temperature of the fish is higher than the water temperature.

The body is completely covered with scales (subfamily Thunnini), forming in the area pectoral fins vaguely defined armor in the form of a bib. The pectoral fins are short and do not reach the beginning of the second dorsal fin.

Gill rakers 37. Vertebrae 39-41; behind the dorsal and anal fins there are nine additional fins.

Related forms. Our waters are home to albacore, Germo alamnga, and yellowfin tuna, Neothunnus macropterus. Both species are distinguished from tuna by long pectoral fins that extend noticeably beyond the beginning of the second dorsal fin. In appearance it is similar to tuna bonito, Sarda sarda.

Spreading. In Europe - Mediterranean and Black Sea; East End Atlantic Ocean, from the coast of Morocco - in the south to Iceland and the northern coast of Norway - in the north (also found off the coast of Murman); North Sea, Kattegat, Baltic Sea; near the Azores and Canary Islands; atlantic coast North America, from Cape Hatteras (North Carolina) to Nova Scotia.

In the Pacific Ocean - along the coast of North America, from lower California (Mexico) to Oregon and off the coast of Asia north to about. Simushira (Kuril Islands).

In Russia, it is distributed in the Black and Japanese (Peter the Great Bay) seas. Enters the Sea of ​​Azov. How rare, in the Barents Sea.

BIOLOGY OF COMMON TUNA

Characteristic. Tuna is a warm-water schooling fish of the surface layers of the sea (pelagic), making significant migrations. The body temperature of tuna is several degrees (up to 9) higher than the temperature of the surrounding water.

Spawning. In the Mediterranean and Black Seas (near the Bosphorus) it occurs in May-July, in the Sea of ​​Japan, apparently, at the end of summer. Off the coast of California, spawning occurs presumably from December to May. Off the coast of Japan, the optimal water temperature in tuna spawning areas is 20-21°.

Development. Pelagic caviar, spherical in shape, with a diameter of 1.05-1.12 mm; contains a drop of fat yellow color, with a diameter of 0.25-0.28 mm. The development of eggs lasts no more than two days. Newly hatched larvae are 3 mm long.

The fry grow very quickly, reaching an average weight of 45 g in July, 120 g in August, 300-500 g in September and 900 g in October (Mediterranean Sea).

Height. Reaches a length of 3 m and weighs up to 6 c.

Tuna becomes sexually mature in the third year of life, having a length of about 1 m and a weight of about 15 kg (Mediterranean Sea). Average weight commercial fish off the coast of Japan (southeastern coast of Hokkaido) 37.5-112.5 kg.

Nutrition. Predator. The main food (in the Sea of ​​Japan) is sardines, herring, anchovies. Pursuing these fish, tuna sometimes go north to latitudes that are not usually visited by them. IN northern seas Tuna food also consists mainly of fish: herring, mackerel (mackerel), sprat, sardine, anchovy, garfish, spiny shark, as well as cuttlefish, etc.

Migrations. It enters the Black Sea, to the shores of the Crimea and the Caucasus, from the Mediterranean; occasionally enters the Sea of ​​Azov. Tuna enters the Black Sea from April to early September and returns in early October to the Sea of ​​Marmara, where some of the fish remain for the winter and some go to the Mediterranean Sea. In the spring, with warming, tuna rise to the surface from the depths where they spent the winter, and then approach the shores.

In the Sea of ​​Japan in winter it stays near southern parts coast of Japan to 32° N. latitude, in the spring it begins to move north and in the summer it reaches 46° N. w. During feeding migrations to the north, tunas come close to the shores along with schools of fish that they feed on.

Young tuna are found near east coast Korea in waters with temperatures from 5 to 20° (in the largest quantities at a temperature of 10-15°). Optimal temperature water for adults 15-17°, fluctuations from 10 to 27°.

In the Sea of ​​Japan off the coast of Russia, tuna are found from late May to September in Peter the Great Gulf and further north; tuna appear in Preobrazheniya, Valentina, Vladimir, and Vanina bays in large flocks, sometimes grouping into huge flocks near the islands of Peter the Great Bay.

COMMON TUNA FISHERY

The importance of tuna in the world fishery is very great, especially due to the high value of its meat, which is almost entirely canned. In the seas of the Atlantic Ocean, approximately 250 thousand quintals are mined different types tuna (genus Thunnus and related ones); also in the pool Mediterranean Sea about 40 thousand c and in the Pacific seas 1000-1200 thousand c (1935-1939).

There was no special tuna fishery in Russia, but it was apparently possible to organize it.

Technology and progress of the fishery. In California in 1937, a special tuna fleet open sea consisted of 70 ships. 50 of these vessels, more than 90 feet (27 m) long, are equipped with diesel engines, are fast and are capable of going out to sea at a distance of up to 3 thousand miles, making voyages of 6 - 8 thousand miles. The catch per trip is 1.5-3.5 thousand. c. In Japan, off the coast, tuna is caught with stationary coastal traps (stoshi-daibo-ami), in the open sea with purse seines, floating nets, and hook gear.

In southern Europe and off the coast of Africa, tuna is caught in madrags (set nets) from May to July, that is, during the spawning period or immediately after it ends. During the rest of the year they fish with hook and line gear.

Usage . Tuna meat is divided into light (white) and dark (red). Light meat is fattier than dark meat, its fat content reaches 12-14%. The meat is mainly used for the production of highly valuable canned food (in oil), and is partially consumed fresh.

Among the types of fish, tuna is the most popular. Its value is increasingly increasing, since every year the population faces a significant reduction in numbers. Tuna is also called the “rose of the seas” for the corresponding color of its meat. Why is tuna so popular? Let's consider its characteristics.

Benefit

Laboratory studies indicate that tuna has a great positive effect on human tissues and organs.

1. Fish meat contains essential fatty acids that have a positive effect on the heart and vascular system and brain function. Cholesterol levels decrease when eating tuna.
2. The quality of tuna is undeniable as it is not contaminated harmful substances and organisms.
3. With regular consumption of tuna meat, the possibility of developing cancer tumors is excluded.
4. Has a positive effect on nervous system and the emotional background of a person.
5. Tuna meat can normalize blood sugar levels.
6. Improves the physical condition of older people.
7. Eating tuna meat prevents blockage of arteries, reducing the number of cholesterol plaques.
8. Tuna dishes normalize the nervous system.
9. The protein contained in tuna is 95 percent digestible, which is why this fish is a favorite dish for bodybuilders.
10. With constant consumption of tuna, a person gets sick less colds, immunity becomes stronger.
11. Consuming tuna regularly increases your metabolic rate.
12. Tuna meat relieves allergic effects.

Harm

Despite the advantages of tuna listed above, its meat can cause some harm: in this fish, as in all predatory fish, mercury may accumulate, so tuna dishes should be consumed with caution. It is also recommended to limit the consumption of this fish during pregnancy, especially with toxicosis.

Contraindications

Tuna meat is so healthy that the only contraindications include individual intolerance to this species fish.

Composition (vitamins and minerals)

IN chemical composition tuna meat - many different nutrients: vitamins, minerals, trace elements, etc. Let's consider the quantitative content of such elements in 100 grams of fish meat.

No.	vitamins and minerals	quantity in 100 grams	what does it affect?
1	vitamin A (retinol acetate)	0.89 mg	fights the aging of body cells, strengthens the immune system
2	vitamin B1 (thiamine)	0.34 mg	thanks to this element, stable metabolism of carbohydrates and fats is established
3	vitamin B2 (riboflavin)	0.17 mg	strengthens nails, hair follicles, improves appearance skin
4	vitamin B3 (niacin)	0.03 mg	has a vasodilating effect, lowers cholesterol, calms the nervous system
5	vitamin D (ergocalciferol)	0.56 mg	protects against the development of rickets, osteoporosis
6	iron	1.67 mg	Helps maintain hemoglobin levels in the blood
7	copper	2.23 mg	participates in bone tissue regeneration
8	zinc	0.9 mg	has a remarkable healing effect, supports hormonal levels
9	selenium	3.44 mg	has antioxidant properties

The nutritional value of tuna meat is 130 calories.

How to cook

Tuna is a very fatty fish, but it can dry out quickly, so you need to purchase it either fresh or packaged in airtight packaging. The color of fresh tuna meat should range from light pink to bright pink. The fish carcass is usually large in size, which is why it is most often sold in the form of steaks. It is important not to make a mistake here: the steak should give off a fresh and pleasant smell, without inclusions fish oil. What's the best way to cook tuna meat? Below are some classic recipes.

1. Fried tuna in a frying pan. Pour 2-3 tablespoons of olive oil into a deep frying pan, heat it and add tuna steaks (no more than 3 cm thick), pre-washed under running water and lightly wrung out, and fry over medium heat. Frying time is 9-12 minutes. The finished fish should flake but retain its pink color. For lovers of unusual cuisine, we recommend breading steaks in beaten egg and sesame seeds with the addition of spices before frying.
2. Baked tuna in the oven. First you need to preheat the oven to 200-220 degrees. Pour a little onto a baking sheet vegetable oil, place the steaks 2-2.5 cm thick, brush the top with melted butter, sprinkle with salt and spices and bake for 7-10 minutes. You don't need more time to bake tuna because it cooks very quickly and then starts to dry out.
3. Marinated tuna. To marinate tuna, you can prepare the following composition: 2 parts soy sauce, 1 part lemon juice, 1 part sesame oil, salt to taste. Tuna fillet 1.5-2 cm thick is placed in a glass container, poured with the prepared marinade and left for 10-13 hours, after which the marinade is drained and the fillet is slightly dried. Serve with olive oil, sprinkled with green onions.

Storage

You can store fresh tuna for 1 day; it is better to cook it immediately after purchase. As an option, freeze the fish pieces by first wrapping them in cellophane. If we're talking about about storing canned tuna, this period is indicated on the packaging and is usually 2 years.

How to choose

Tuna sold in supermarkets all year round, but the most best time shopping - May-September. How to choose the right fish? It has already been said that tuna is a rather oily fish, so it must be very fresh. When choosing, you need to pay attention that the meat is dense, firm, the color is from pink to red, and the aroma is pleasant meaty. Fish that is not quite fresh is discolored near the bones or has a brown tint.

What goes with it?

Tuna is often used in canned food, which sounds very harmonious in salads. Canned tuna is combined with boiled potatoes, blanched or green peas, olives, fresh tomatoes and cucumbers, eggs, cheese.

Tuna is a universal fish, so you can always quickly prepare delicious and healthy dishes. This is especially true for canned tuna, because there are a huge number of recipes for preparing dishes containing it.

Its fertility varies from 2.9 to 6.3 million eggs, spawned in several portions; embryonic development at 28-29°C it ends, like other tuna, very quickly - after 21 hours. Bigeye tuna feed on a wide variety of animals. Especially great importance This species' food includes deep-sea and semi-deep-sea fish - crabbills, alepisaurs, godwit, hempilidae, as well as squid, pelagic octopuses, and large shrimp. Bigeye tuna reaches a length of 45-50 cm by the end of the first year of life, 70 cm at two years of age and 155 at the age of six, with sexual maturity occurring at a length of 90-100 cm. The largest known specimen of this species was caught off the coast of Peru : its length was 236 cm and its weight was 197 kg.

Longfin tuna / Thunnus alalunga

Longfin tuna, also called albacore, are characterized by very large pectoral fins. Unlike bluefin tuna, this fish lives primarily in the open ocean and rarely appears off the coast. Albacore is found only in oceanic salinity, but tolerates significant temperature changes (from 12-14 to 23 ° C). The boundaries of the distribution area of ​​this species in all oceans lie in the region of forties latitudes, but in some places (for example, in the Gulf of Alaska) longfin tuna is also found outside this zone.

Longfin tuna

On the periphery of the range, only immature fish aged 2-6 years are found, which live exclusively in the upper, warmest layer of water. Sexually mature large fish They stay in the tropical zone, but, unlike young ones, they do not live near the surface, but at a depth of 150-200 m. Albacore’s food in moderately warm waters consists of fish, squid and crustaceans that live in the surface layer (in the North Pacific Ocean, for example , one of the main food items is saury). In the tropics, longfin tuna eats deeper-sea animals - gempilas, sea bream, and some cephalopods. Albacore spawning occurs near the borders tropical region in spring summer time the corresponding hemisphere. The fertility of this fish reaches 2.5 million eggs. Longfin tuna grows slower than tropical species real tuna. It becomes sexually mature at the age of 4-5 years, with a length of about 90 meters, and maximum dimensions reach 1.3 m with a weight of 45 kg. This fish makes long migrations. In the northern half of the Pacific Ocean, for example, flocks of immature albacore constantly move between the shores of America and Japan, following very specific paths. These migrations were tracked by tagging fish, which made it possible to determine their speed, averaging 16-17 nautical miles per day. Long-distance migrations are apparently characteristic of other albacore populations.

Yellowfin Tuna / Thunnus albacares

Within the tropical region, they are found everywhere, but the frequency of their occurrence is largely determined by feeding conditions: the areas of the largest concentrations of this species are confined to waters with high biological productivity, abundant in food. The food spectrum of yellowfin tuna is very diverse, which is undoubtedly due to the lack of any selectivity in nutrition in this species (like other tunas). Yellowfin tuna feeds everywhere on any organisms that come their way. Suffice it to note that fish belonging to 50 different families were found in the stomachs of this predator. In small fish living near the surface, the food composition is dominated by near-surface fish, cephalopods and crayfish; in larger ones - squids and fish living at medium depths, among which sea bream, gempilas, and juvenile sunfish are especially common. Yellowfin tuna reaches 2 m in length and weighs 130 kg. This species is characterized by very rapid growth: the annual increase in length, according to secondary catches of tagged fish, is 20-40 cm. Already at the age of two, the fish weigh about 13 kg, and at the age of four - 60 kg. Puberty occurs when it reaches 50-60 cm in length, and fecundity is about 1 million eggs in small fish and reaches 8.5 million in large fish. Spawning of yellowfin tuna in the tropical zone occurs in all seasons of the year, but at its edges it is limited to the summer months. Within the species' range, there are likely to be numerous populations of yellowfin tuna in isolated areas. Some populations are characterized by fairly extensive migrations, others lead a more or less sedentary lifestyle. Yellowfin tuna does not undergo transoceanic movements similar to those noted for bluefin tuna and albacore.

Mackerel tuna / Auxis thazard

Atlantic small tuna / Euthunnus alleteratus

Small spotted tuna / Euthunnus affinis

Puberty occurs at a length of 40-45 cm, and the maximum length is 87 cm with a weight of 8.6 kg. Spawning in the tropical zone occurs year-round, but seasonal peaks of spawning are well defined almost everywhere. At the borders of the range, reproduction is limited to the warm season. This tuna stays near the surface and is usually found in schools, each of which consists of 100-5000 individuals, similar in body length. Sometimes spotted tuna form mixed schools with similar-sized yellowfin and mackerel tuna or mackerel mackerel (genus Megalaspis). In the diet of this species, the main role is played by invertebrates - juvenile crustaceans, cephalopods, pteropods - and small fish, mainly anchovies, sardinella, silversides, flying fish, horse mackerel.

Skipjack Tuna / Katsuwonus pelamis

In some areas, skipjack tuna undertake quite significant seasonal movements and penetrate into moderately warm water areas in the summer. Such migrations are very well expressed, in particular, off the coast of Japan: in summer, aggregations of skipjack spread to the latitude of northern Hokkaido, and individual groups of fish even reach Kuril ridge. Skipjack tuna adheres to well-warmed waters and is most often found at temperatures of 17-28 ° C. A schooling lifestyle is very typical for this species. Dense schools of skipjack are formed from fish of similar sizes that have equal abilities for active movement. These flocks can be very large, sometimes containing tens of thousands of individuals. In addition to “pure” schools, collective aggregations are often observed, in which it feeds together with yellowfin tuna, and sometimes with dolphins. Moving flocks develop high speeds, reaching up to 45 km/h. Individual skipjack fertility ranges from 100 thousand eggs with a length of 40 cm to 2 million with a length of 75 cm. Judging by the findings of larvae and fry, spawning of this species occurs only in tropical waters and the spawning area occupies only part of the total distribution area. Skipjack is the smallest of the open ocean tunas. He's only in in rare cases reaches a length of 1 m and a weight of 25 kg (usual dimensions do not exceed 50-60 cm and a weight of 3-5 kg). Sexual maturation of this fish occurs when it reaches a length of about 40 cm, apparently in the second or third year of life. The food of skipjack tuna consists of relatively small fish, squid and crustaceans living in the surface layers. In different areas, the composition of food items can vary significantly. Thus, in the central part of the Pacific Ocean, fish make up about 75%, shellfish (mainly squid) - about 20% and crustaceans only 4% of the skipjack's food, and in the eastern part of the Pacific Ocean the corresponding groups account for 33, 4 and 62%. The consolidated list of food items for this species in the Pacific Ocean includes more than 180 pelagic animals.

Bluefin Tuna / Thunnus thunnus

Other habitat areas of this species are confined to the Atlantic coasts of America, South and East Africa, Australia, New Zealand, Chile, Peru, California. IN summer months Bluefin tuna is often found in Soviet Far Eastern waters - off the coast of Primorye and Southern Sakhalin. Bluefin tuna is a schooling fish, most common in coastal waters, although found far from the coast. This is the largest of the tunas, sometimes exceeding 3 m in length and weighing up to 375 kg. It has a fast growth rate and reaches a length of 1 m at the age of three years and 2 m at the age of 7-9 years. Its food is very varied and consists of any fish and invertebrates that are quite abundant in the feeding area. The main breeding areas are located in subtropical areas, including the Mediterranean Sea. The individual fertility of large individuals reaches 10 million eggs. Bluefin tuna in all parts of the species range makes seasonal migrations, moving mainly along the coast. The migrations of this fish in open waters are poorly studied, but it is known that some individuals can even make transoceanic movements. In particular, cases of secondary capture of fish tagged off the coast of Mexico were noted in the Tokyo area - in 5800 nautical miles from the marking site. In the Atlantic Ocean, individuals with tags attached off Florida were caught in the Bay of Biscay.

Tuna is a fish with a torpedo-shaped body that is ideal for constant movement. Moreover, these fish move constantly, without stopping for a minute. The energy that the tuna expends when swimming made its blood several degrees higher than the temperature of the surrounding water.

Tuna move in large schools and cover long distances in search of food, moving at speeds of up to 77 km/h.

Albacore

Albacore is a type of tuna that is sometimes called albacore tuna. This species is distributed in almost all waters of the world's oceans, with the exception of polar regions. Albacore is not enough major representative family, reaching a length of almost 1.5 m. It is a very significant object of industrial fishing due to its high-quality meat. Longfin tuna meat is most widely distributed in the United States, where this species is often simply called “tuna.” Albacore - a favorite trophy sea ​​fish tins

Bigeye tuna

Bigeye tuna is a larger member of the family, growing up to 2.5 m. The maximum recorded weight of this fish was 400 kg. Distinctive feature This tuna has a wide fin that has 13 or 14 dorsal spines. During migration, bigeye tuna can descend into cold, deep-sea layers of water, which most species of the family do not visit. In these areas, the tuna actively feeds, while its heart functions more actively, giving vitality fish. But the fish cannot stay in the cold depths for a long time and must necessarily warm up in the warmth on the surface.

Blackfin tuna

Blackfin tuna is the smallest. Does not exceed 1 m in length and 20 kg in weight. It lives only in the western Atlantic Ocean off the coast of Brazil. Unlike their counterparts, blackfin prefer to eat small larvae, shrimp, crabs and squid. Of course, they also hunt small fish, but to a lesser extent. This species ages very quickly, and a 5-year-old fish is already considered old.

Bluefin tuna

Bluefin tuna is an inhabitant of the Pacific Ocean. One of the largest and fastest fish. Having warm blood that warms the fish's muscles, providing additional energy, bluefin tuna is a fast predator. Its diet is replete with herring, mackerel and squid, which slower predators cannot catch.

Atlantic bluefin tuna

Atlantic bluefin tuna - found throughout the Atlantic. In the past, this type of tuna was found in the Black Sea, but currently the Black Sea population has disappeared. Visually, the bluefin tuna's body is similar to the Pacific bluefin, and in the past they were often confused as one species. This tuna is the most valuable among other species. There are known cases of buying bluefin tuna carcasses for more than 100 thousand dollars. This is the kind of money the Japanese are willing to pay for tuna meat, which is used in preparing many national dishes.

Tunas are a whole tribe of mackerel, covering 5 genera and 15 species. Tuna has long been a commercial fish, according to historical information Japanese fishermen caught tuna 5 thousand years ago. The name of the fish comes from the ancient Greek “thyno”, which means “throw, rush”.

Description and features of tuna

All varieties of tuna are characterized by an elongated body shaped like a spindle, which sharply tapers towards the tail. One dorsal fin has a concave outline and is quite elongated, while the second is sickle-shaped, thin and similar in appearance to the anal fin. From the second dorsal fin to the tail, another 8-9 tiny fins are visible.

The tail resembles a crescent moon. It is he who performs the locomotive function, while the body, round in diameter, remains practically motionless when moving. Tuna has a large cone-shaped head with small eyes and a wide mouth. The jaws are equipped with small teeth arranged in one row.

The scales covering the body of the tuna in the front part of the body and along the sides are an order of magnitude thicker and larger; they create something like a protective shell. The color depends on the species, but all are characterized by a darker back and a lighter belly.

Tuna fish has a rare property - they are able to maintain elevated temperature body, relative external environment. This ability, called endothermy, is seen only in tunas and herrings.

Thanks to this, tuna can develop colossal speeds (up to 90 km/h), spend less energy on it and adapt to conditions much better environment, unlike other fish.

Helps tuna “warm up” the blood the whole system small vessels, with both venous and arterial blood, which are intertwined and concentrated on the sides.

Warm blood in the veins, heated by muscle contractions, compensates for the cold blood in the arteries. Experts call this vascular sideband “rete mirabile” - “magic network”.

Tuna meat, unlike most fish, has a red-pink hue. This is explained by the presence in the blood of fish of a special protein, myoglobin, which contains a lot of iron. It is produced when driving at high speed.

IN description of tuna fish It is impossible not to touch upon the culinary issue. In addition to its excellent taste, tuna meat is more like beef; French restaurateurs call it “veal of the sea” for its unusual taste.

The meat contains a whole range of microelements, amino acids and vitamins that are beneficial for the body. Regular consumption of it reduces the risk of cancer and heart diseases, improves immunity and improves the condition of the body as a whole.

In the USA, for example, tuna dishes are mandatory on the menus of researchers and university students. The substances included in its composition improve brain activity.

Pictured is tuna meat

• ordinary;
• Atlantic;
• mackerel;
• striped (skipjack);
• longfin (albacore);
• yellowfin;
• big-eyed.

Ordinary tuna - fish size extremely impressive. It can grow up to 3 m in length and weigh up to 560 kg. Top part body, like all fish living in surface waters, painted in dark color. In the case of ordinary tuna, it is deep blue, for which this species is also called bluefin tuna. The belly is silvery-white, the fins are brown-orange.

Common tuna

Atlantic (black tuna) has a length of about 50 cm, with a maximum of 1 m. Of the recorded cases, the largest weighed 21 kg. Unlike others fish family, tuna The blackfin lives only in a limited area in the Western Atlantic.

Atlantic tuna

Mackerel tuna is a small resident coastal areas: length – no more than 30-40 cm, weight – up to 5 kg. The body color is not much different from the others: black back, light belly. But you can recognize it by its two-color pectoral fins: with inside They are black and purple on the outside.

Mackerel tuna

Skipjack tuna is the smallest inhabitant of the open ocean among its own kind: on average it grows to only 50-60 cm, rare specimens - up to 1 m. distinctive feature are dark, well-defined longitudinal stripes on the abdominal part.

Pictured is skipjack tuna

Longfin (white tuna) - sea fish up to 1.4 m long, weighing up to 60 kg. The back is dark blue with a metallic tint, the belly is light. It is called longfin due to the size of its pectoral fins. White tuna meat is the most valuable; there have been cases when Japanese chefs bought the carcass for $100,000.

Longfin tuna pictured

Yellowfin tuna sometimes reaches 2-2.5 m in length and weighs up to 200 kg. It got its name from the bright yellow coloring of its dorsal and anal fins. The body is gray-blue on top and silver underneath. Along the lateral line there is a lemon and blue stripe, although in some individuals it may be absent.

Pictured is yellowfin tuna

Bigeye tuna, in addition to the size of its eyes, has another feature that distinguishes it from its closest relatives. This is deep sea type of tuna fish lives at a depth of more than 200 m, and only young animals stay near the surface. Large individuals reach 2.5 m and weigh more than 200 kg.

Bigeye tuna fish

Tuna Lifestyle and Habitat

Tunas are schooling pelagic, preferring warm water with high salinity. They excellent swimmers, swift and dexterous. Tuna constantly needs to be on the move, since this is the only way there is a sufficient flow of oxygen through the gills.

Tuna migrate seasonally along the coasts and travel considerable distances in search of food. Accordingly, tuna fishing occurs at a certain time when the concentration of fish in the area is maximum. Rarely a fisherman would not dream of doing photo of tuna fish with human height.

water areas, where does tuna fish live?– are huge. Thanks to the increased blood temperature, the fish feels comfortable both at +5° and +30°. The habitat of tuna covers the tropical, subtropical and equatorial waters of three oceans: Indian, Atlantic and Pacific. Some species prefer shallow water near the coast, others, on the contrary, prefer the simplicity of open water.

Tuna nutrition

Tunas are predatory fish. They hunt for smaller prey, eat a variety of fish, and also like to taste fish. After a couple of seconds, the giant came to his senses and spat out the bird, but the width of his mouth and speed of reaction amazed everyone around him.

Reproduction and lifespan of tuna

IN equatorial zone, tropics and some areas subtropical zone(Southern Japan, Hawaii) tuna spawning occurs year-round. In more temperate and cool latitudes - only in the warm season.

A large female can spawn up to 10 million eggs no larger than 1 mm in size at a time. Fertilization occurs in water, where the male releases his seminal fluid.

After 1-2 days, the eggs begin to hatch into fry. They immediately begin to feed on their own and quickly gain weight. Young animals, as a rule, stay in the upper warm layers waters rich in small crustaceans and plankton. Tuna reaches sexual maturity at the age of 3 years, lives on average 35, some individuals - up to 50.

Due to environmental degradation and merciless overfishing, many species of tuna are on the verge of extinction. Greenpeace has added tuna to its Red List of foods to avoid in order to preserve the numbers of endangered species and not harm the ecosystem.